1. Technical Field
The system and method described herein relate to packet storm control in a network.
2. Discussion of the Related Art
Computer networks provide a variety of means for transmitting electronic data packets. In conventional unicast networking, packets are transmitted via a network between two devices; each device having a particular network address. A one-to-one relationship is maintained between these two devices for the duration of a session. Broadcast networking operates similarly, insofar as packets are transferred directly from one device to another, yet rather than being transmitted to and received by only one device, broadcast packets are transmitted to and received by all devices on a network.
In multicast networking, network traffic does not travel from one device directly to another. Rather, packets are transmitted from a device to an address that is contained within a lookup table in a switching device, such as a router or switch. A multicast client situated on the network may notify the router that it desires to receive the multicast stream, and, when so informed, the router replicates the traffic and transmits it to that client, and to any other client that similarly joins the session. In this fashion, multiple devices situated on a network may receive particular multicast packets transmitted thereupon, yet other devices situated on the same network may not be in receipt of the same packets.
Excessive broadcast and multicast packets may be detrimental to network performance, because every device residing on the network may process each broadcast and multicast packet. In addition, if packets from a specific device or a specific group of device produce an excessive amount of packets, network performance may also be degraded. Also, destination unresolved unicast packets may degrade network performance. A destination unresolved unicast packet is a packet in which the destination address does not have an address in the lookup table, and thus the switching device does not know where to transmit the packet. The switching device receives the destination unresolved unicast packet and transmits it to devices residing on a virtual local area network with the switching device. If large numbers of devices are present on the VLAN, excessive packet traffic may occur and degrade network performance.
Additional processing overhead required by either broadcast packets, multicast packets, destination unresolved unicast packets or excessive packets from a device or group of devices may cause a device to deny services or drop incoming packets from other devices. This occurrence may be called a packet storm, e.g., a broadcast storm or a multicast storm.
Unlike unicast packets, multicast packets can be identified by an odd value in the first bit of the first byte of the destination Media Access Control (“MAC”) address. Broadcast packets are identified as having all ones in the destination MAC address. If a device or group of devices are transmitting excessive packets, the packets can be identified by the originating/transmitting device address in the MAC address. By recognizing these distinctions among various packet types, a suppression system may be established to implement packet storm control.